1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * iSCSI over TCP/IP Data-Path lib
4 *
5 * Copyright (C) 2008 Mike Christie
6 * Copyright (C) 2008 Red Hat, Inc.  All rights reserved.
7 * maintained by open-iscsi@googlegroups.com
8 */
9
10#ifndef LIBISCSI_TCP_H
11#define LIBISCSI_TCP_H
12
13#include <scsi/libiscsi.h>
14
15struct iscsi_tcp_conn;
16struct iscsi_segment;
17struct sk_buff;
18struct ahash_request;
19
20typedef int iscsi_segment_done_fn_t(struct iscsi_tcp_conn *,
21				    struct iscsi_segment *);
22
23struct iscsi_segment {
24	unsigned char		*data;
25	unsigned int		size;
26	unsigned int		copied;
27	unsigned int		total_size;
28	unsigned int		total_copied;
29
30	struct ahash_request	*hash;
31	unsigned char		padbuf[ISCSI_PAD_LEN];
32	unsigned char		recv_digest[ISCSI_DIGEST_SIZE];
33	unsigned char		digest[ISCSI_DIGEST_SIZE];
34	unsigned int		digest_len;
35
36	struct scatterlist	*sg;
37	void			*sg_mapped;
38	unsigned int		sg_offset;
39	bool			atomic_mapped;
40
41	iscsi_segment_done_fn_t	*done;
42};
43
44/* Socket connection receive helper */
45struct iscsi_tcp_recv {
46	struct iscsi_hdr	*hdr;
47	struct iscsi_segment	segment;
48
49	/* Allocate buffer for BHS + AHS */
50	uint32_t		hdr_buf[64];
51
52	/* copied and flipped values */
53	int			datalen;
54};
55
56struct iscsi_tcp_conn {
57	struct iscsi_conn	*iscsi_conn;
58	void			*dd_data;
59	int			stop_stage;	/* conn_stop() flag: *
60						 * stop to recover,  *
61						 * stop to terminate */
62	/* control data */
63	struct iscsi_tcp_recv	in;		/* TCP receive context */
64	/* CRC32C (Rx) LLD should set this is they do not offload */
65	struct ahash_request	*rx_hash;
66};
67
68struct iscsi_tcp_task {
69	uint32_t		exp_datasn;	/* expected target's R2TSN/DataSN */
70	int			data_offset;
71	struct iscsi_r2t_info	*r2t;		/* in progress solict R2T */
72	struct iscsi_pool	r2tpool;
73	struct kfifo		r2tqueue;
74	void			*dd_data;
75	spinlock_t		pool2queue;
76	spinlock_t		queue2pool;
77};
78
79enum {
80	ISCSI_TCP_SEGMENT_DONE,		/* curr seg has been processed */
81	ISCSI_TCP_SKB_DONE,		/* skb is out of data */
82	ISCSI_TCP_CONN_ERR,		/* iscsi layer has fired a conn err */
83	ISCSI_TCP_SUSPENDED,		/* conn is suspended */
84};
85
86extern void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn);
87extern int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
88			      unsigned int offset, bool offloaded, int *status);
89extern void iscsi_tcp_cleanup_task(struct iscsi_task *task);
90extern int iscsi_tcp_task_init(struct iscsi_task *task);
91extern int iscsi_tcp_task_xmit(struct iscsi_task *task);
92
93/* segment helpers */
94extern int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn);
95extern int iscsi_tcp_segment_done(struct iscsi_tcp_conn *tcp_conn,
96				  struct iscsi_segment *segment, int recv,
97				  unsigned copied);
98extern void iscsi_tcp_segment_unmap(struct iscsi_segment *segment);
99
100extern void iscsi_segment_init_linear(struct iscsi_segment *segment,
101				      void *data, size_t size,
102				      iscsi_segment_done_fn_t *done,
103				      struct ahash_request *hash);
104extern int
105iscsi_segment_seek_sg(struct iscsi_segment *segment,
106		      struct scatterlist *sg_list, unsigned int sg_count,
107		      unsigned int offset, size_t size,
108		      iscsi_segment_done_fn_t *done,
109		      struct ahash_request *hash);
110
111/* digest helpers */
112extern void iscsi_tcp_dgst_header(struct ahash_request *hash, const void *hdr,
113				  size_t hdrlen,
114				  unsigned char digest[ISCSI_DIGEST_SIZE]);
115extern struct iscsi_cls_conn *
116iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
117		     uint32_t conn_idx);
118extern void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn);
119
120/* misc helpers */
121extern int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session);
122extern void iscsi_tcp_r2tpool_free(struct iscsi_session *session);
123extern int iscsi_tcp_set_max_r2t(struct iscsi_conn *conn, char *buf);
124extern void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
125				     struct iscsi_stats *stats);
126#endif /* LIBISCSI_TCP_H */
127